Studying occult lore, you learn one Eldritch Invocation option of your choice from the warlock class. Your spellcasting ability for the invocation is Intelligence, Wisdom, or Charisma (choose when you select this feat). If the invocation has a prerequisite of any kind, you can choose that invocation only if you’re a warlock who meets the prerequisite.
Whenever you gain a level, you can replace the invocation with another one from the warlock class.
Eldritch Smite:
Once per turn when you hit a creature with your pact weapon, you can expend a warlock spell slot to deal an extra 1d8 force damage to the target, plus another 1d8 per level of the spell slot, and you can knock the target prone if it is Huge or smaller.